Maybe the original hunter was still trying to track it as if their (bad) shot only glanced it it could have traveled a considerable ways and it sounded like it was still traveling.
Could have also been a new /novice/first deer hunter that had the "adrenilin rush" creating a "varience" in prudent aiming. I remember my first deer and the perfect shot that blew its guts instead of the heart/lung shot that I was sure I had taken.
Had to clean it with dad and uncle -- well upwind shouting instructions
I do however agree that we as hunters need to throughly track all our prey. I have found numerous dead critters that had wounds that would have left plenty of sign to follow but obviously weren't tracked.